Load data for .257 Roberts + .257 | 100gr | Sierra HPBT MatchKing

Recommended Powder(s): Alliant Reloder-17, ReloadSwiss RS 52, ReloadSwiss RS 60, Rottweil R 903, Somchem S355

Load Specifications

(Use the Personalized Load Calculator below to adjust )

Bullet:	.257 \| 100gr \| Sierra HPBT MatchKing
Manufacturer SKU:	1628
Bullet Weight:	100gr \| 6.5g
Bullet Diameter:	0.257" \| 6.53mm
Bullet Length:	1.083" \| 27.5mm
Caliber:	.257 Roberts load data
Case Length (l3):	2.233" \| 56.7mm
Cartridge Length (C.O.L.):	2.733" \| 69.4mm
Seated Depth:	0.583" \| 14.8mm
Shank Seated Depth:	0.453" \| 11.5mm
Case Capacity:	56.0 Grains of Water \| 3.64 cm³
Primer Size:	Large Rifle (LR)
Max. allowed Pressure:	51488 psi \| 3550 bar
LID:	LID_B5792_C241
Last updated:	2025-02-02
Recommended Twist Rate:	1:10 - 1:9

Load data for 120 loads in caliber .257 Roberts with .257 | 100gr | Sierra HPBT MatchKing bullet and 60 powders such as Alliant Reloder-17, ReloadSwiss RS 52, ReloadSwiss RS 60, Rottweil R 903, Somchem S355. The key underlying parameters are shown in the table above.

Important Notice: DO NOT go below Minimum Charge or above Maximum Charge unless there are reasons. Since xxlreloading.com has no control over the equipment and components used by the customer and the data used in connection with the website, any responsibility and liability for the results achieved is rejected. Also see our Terms of Service.

Questions regarding the load data: Please read the information in the next tab "Explanations".
A load must fulfill certain criteria to be listed in the default view below - see "powder criteria to fulfill to be listed".

Our load data might deviate from other sources - see the "most common reasons for deviations".

All loads are based on the bullet and case dimensions shown under "Load Specifications" - see "reloading suggestions" if you deviate.

You can set your specifications in the "Personalized Load Calculator".

Go to the bottom of the "My Account " page to set the measure system (imperial vs. metric)
Muzzle velocity vs. barrel length
Every 1 inch additional barrel length increases muzzle velocity by approx. 33.2 fps
C.O.L. (Inch)
C.O.L. (mm)
Case Length (Inch)
Case Length (mm)
CaseCapacity (GoW)
Min z (%)
Min FR (%)
Max FR*
Barrel Length (Inch)
Barrel Length (cm)
Safety Buffer (%)
.
Use the Personalized Load Calculator to customize loads to your own specific requirements. Find more details in the help section.

Our default view only displays powders/loads that fulfill certain criteria: Max pressure of a load <=90% of Max. Standardized Pressure. Fill Rate (Min FR): >80% and <100% for rife loads, >60% and <100% for pistol loads. Min. Propellant Combustion (Min z): >90% for rifle loads , >80% for pistol/revolver loads. Relax these criteria at your own risk to potentially get more powders shown in the load tables.

Click on the desired row in the tables below to add a specific load / powder to your Diary and manage there.

Powder	Charge	FR	MaxP	%	V(0)	z
ADI AR 2208	<<locked>>	87%	45876	89%	**81	98%
[Accurate 2700]*	<<locked>>	88%	45658	89%	**02	93%
Accurate 4064	<<locked>>	87%	45716	89%	**00	100%
Accurate 4350	<<locked>>	96%	45905	89%	**66	97%
Alliant Reloder- TS 15.5	<<locked>>	88%	46267	90%	**20	99%
Alliant Reloder-15	<<locked>>	85%	45571	88%	**13	98%
Alliant Reloder-16	<<locked>>	96%	45818	89%	**89	98%
Alliant Reloder-17 👍	<<locked>>	91%	45411	88%	**09	99%
Alliant Reloder-23	<<locked>>	97%	33243	65%	**03	95%
[Alliant Reloder-26]*	<<locked>>	97%	36782	71%	**48	93%
Hodgdon CFE223	<<locked>>	86%	45498	88%	**49	97%
Hodgdon H380	<<locked>>	87%	45832	89%	**04	97%
[Hodgdon H414]*	<<locked>>	91%	45672	89%	**53	94%
[Hodgdon H4350]*	<<locked>>	97%	45266	88%	**77	93%
Hodgdon Hybrid 100V	<<locked>>	97%	43091	84%	**84	98%
Hodgdon LVR	<<locked>>	93%	45571	89%	**43	96%
[Hodgdon Superperformance]*	<<locked>>	93%	45963	89%	**63	93%
Hodgdon VARGET	<<locked>>	87%	45440	88%	**71	98%
Hodgdon TrailBoss	<<locked>>	97%	33779	66%	**57	100%
IMR 3031	<<locked>>	85%	46224	90%	**27	100%
IMR 4064	<<locked>>	88%	46224	90%	**81	98%
[IMR 4166 Enduron]*	<<locked>>	88%	45745	89%	**38	94%
[IMR 4350]*	<<locked>>	95%	46282	90%	**90	94%
[IMR 4451 Enduron]*	<<locked>>	90%	46122	90%	**74	94%
IMR 4831	<<locked>>	97%	40828	79%	**48	96%
IMR 4895	<<locked>>	85%	45658	89%	**23	98%
Lovex S062	<<locked>>	86%	45774	89%	**77	99%
Lovex S065	<<locked>>	92%	45861	89%	**74	96%
Lovex S070	<<locked>>	94%	46151	90%	**04	95%
Norma 203B	<<locked>>	86%	45847	89%	**23	98%
Norma URP	<<locked>>	96%	45701	89%	**56	97%
Ramshot Big Game	<<locked>>	86%	46079	90%	**46	98%
Ramshot Hunter	<<locked>>	96%	45919	89%	**59	95%
ReloadSwiss RS 14	<<locked>>	95%	33315	65%	**83	100%
ReloadSwiss RS 50	<<locked>>	87%	46151	90%	**87	95%
ReloadSwiss RS 52 👍	<<locked>>	86%	45324	88%	**46	100%
ReloadSwiss RS 60 👍	<<locked>>	93%	45977	89%	**31	100%
ReloadSwiss RS 62	<<locked>>	95%	45382	88%	**76	97%
ReloadSwiss RS 70	<<locked>>	95%	45382	88%	**79	96%
Rottweil R 902	<<locked>>	84%	45745	89%	**64	99%
Rottweil R 903 👍	<<locked>>	90%	46166	90%	**17	99%
[Rottweil R 907]*	<<locked>>	91%	46195	90%	**67	94%
SNPE Vectan SP 11	<<locked>>	89%	45905	89%	**46	98%
SNPE Vectan SP 9	<<locked>>	84%	46253	90%	**07	98%
SNPE Vectan Tubal 5000	<<locked>>	88%	45658	89%	**95	100%
[SNPE Vectan Tubal 7000]*	<<locked>>	93%	45963	89%	**22	94%
Shooters World Long Rifle	<<locked>>	92%	45861	89%	**74	96%
Shooters World Precision	<<locked>>	86%	45774	89%	**77	99%
Somchem S355 👍	<<locked>>	90%	46224	90%	**07	99%
Somchem S365	<<locked>>	97%	42453	82%	**33	99%
Vihtavuori N133	<<locked>>	84%	46224	90%	**02	100%
Vihtavuori N135	<<locked>>	90%	45571	89%	**54	100%
Vihtavuori N140	<<locked>>	85%	46267	90%	**64	100%
Vihtavuori N150	<<locked>>	95%	46050	89%	**81	100%
Vihtavuori N160	<<locked>>	93%	45614	89%	**13	97%
Vihtavuori N540	<<locked>>	85%	45774	89%	**77	100%
Vihtavuori N550	<<locked>>	92%	45832	89%	**56	97%
Vihtavuori N555	<<locked>>	96%	35302	69%	**79	95%
Winchester 6.5 StaBALL	<<locked>>	94%	45876	89%	**94	99%
[Winchester 760]*	<<locked>>	91%	45672	89%	**53	94%

Max Load - Barrel Length: 23.60''

Powder	Charge	FR	MaxP	%	V(0)	z
ADI AR 2208	<<locked>>	81%	37637	73%	**00	96%
[Accurate 2700]*	<<locked>>	83%	38290	74%	**51	90%
Accurate 4064	<<locked>>	81%	38116	74%	**46	100%
[Accurate 4350]*	<<locked>>	82%	28326	55%	**39	90%
Alliant Reloder- TS 15.5	<<locked>>	81%	36956	72%	**26	97%
Alliant Reloder-15	<<locked>>	81%	39827	77%	**89	96%
[Alliant Reloder-16]*	<<locked>>	82%	29544	57%	**52	90%
[Alliant Reloder-17]*	<<locked>>	81%	31821	62%	**57	94%
[Alliant Reloder-23]*	<<locked>>	90%	26876	52%	**93	90%
[Alliant Reloder-26]*	<<locked>>	93%	32227	63%	**07	90%
Hodgdon CFE223	<<locked>>	81%	38029	74%	**85	95%
[Hodgdon H380]*	<<locked>>	81%	37594	73%	**26	94%
[Hodgdon H414]*	<<locked>>	83%	35810	70%	**20	90%
[Hodgdon H4350]*	<<locked>>	91%	38174	74%	**17	90%
[Hodgdon Hybrid 100V]*	<<locked>>	81%	26223	51%	**31	91%
[Hodgdon LVR]*	<<locked>>	81%	31053	60%	**95	91%
[Hodgdon Superperformance]*	<<locked>>	88%	38522	75%	**95	90%
Hodgdon VARGET	<<locked>>	81%	37246	72%	**90	95%
Hodgdon TrailBoss	<<locked>>	81%	26455	51%	**90	100%
IMR 3031	<<locked>>	81%	40030	78%	**02	100%
IMR 4064	<<locked>>	81%	36796	71%	**77	96%
[IMR 4166 Enduron]*	<<locked>>	81%	36956	72%	**35	91%
[IMR 4350]*	<<locked>>	88%	37188	72%	**97	90%
[IMR 4451 Enduron]*	<<locked>>	82%	35592	69%	**35	90%
[IMR 4831]*	<<locked>>	85%	28311	55%	**16	90%
IMR 4895	<<locked>>	81%	40857	79%	**22	97%
Lovex S062	<<locked>>	81%	39030	76%	**36	98%
[Lovex S065]*	<<locked>>	81%	32300	63%	**62	91%
[Lovex S070]*	<<locked>>	85%	34563	67%	**31	90%
Norma 203B	<<locked>>	81%	39334	76%	**82	97%
[Norma URP]*	<<locked>>	82%	29095	57%	**49	90%
Ramshot Big Game	<<locked>>	81%	38696	75%	**85	97%
[Ramshot Hunter]*	<<locked>>	87%	33881	66%	**74	90%
ReloadSwiss RS 14	<<locked>>	81%	26948	52%	**36	100%
[ReloadSwiss RS 50]*	<<locked>>	81%	37956	74%	**03	92%
ReloadSwiss RS 52	<<locked>>	81%	37550	73%	**85	98%
ReloadSwiss RS 60	<<locked>>	81%	31111	60%	**48	95%
[ReloadSwiss RS 62]*	<<locked>>	83%	29689	58%	**85	90%
[ReloadSwiss RS 70]*	<<locked>>	85%	32851	64%	**64	90%
Rottweil R 902	<<locked>>	81%	41017	80%	**59	98%
Rottweil R 903	<<locked>>	81%	34272	67%	**57	96%
[Rottweil R 907]*	<<locked>>	84%	37014	72%	**71	90%
SNPE Vectan SP 11	<<locked>>	81%	35230	68%	**10	95%
SNPE Vectan SP 9	<<locked>>	81%	42554	83%	**28	98%
SNPE Vectan Tubal 5000	<<locked>>	81%	37086	72%	**31	100%
[SNPE Vectan Tubal 7000]*	<<locked>>	84%	34693	67%	**85	90%
[Shooters World Long Rifle]*	<<locked>>	81%	32300	63%	**62	91%
Shooters World Precision	<<locked>>	81%	39030	76%	**36	98%
Somchem S355	<<locked>>	81%	35389	69%	**74	96%
[Somchem S365]*	<<locked>>	81%	25353	49%	**54	92%
Vihtavuori N133	<<locked>>	81%	42134	82%	**23	100%
Vihtavuori N135	<<locked>>	81%	34301	67%	**28	100%
Vihtavuori N140	<<locked>>	81%	40451	79%	**53	100%
Vihtavuori N150	<<locked>>	81%	29747	58%	**13	96%
[Vihtavuori N160]*	<<locked>>	81%	31198	61%	**72	92%
Vihtavuori N540	<<locked>>	81%	40103	78%	**66	100%
[Vihtavuori N550]*	<<locked>>	81%	31328	61%	**12	92%
[Vihtavuori N555]*	<<locked>>	89%	27572	54%	**46	90%
[Winchester 6.5 StaBALL]*	<<locked>>	81%	30081	58%	**16	94%
[Winchester 760]*	<<locked>>	83%	35810	70%	**20	90%

Start Load - Barrel Length: 23.60''

Any powder missing? Then click here.

FR ... fill rate of the cartridge in percent

MaxP ... max. pressure of load in psi or bar

% ... max. pressure of load in percent of the maximum allowed pressure for this caliber

V(0) ... muzzle velocity in feet per second (fps) or meters per second (m/s)

z ... powder burnt in percent

[...] *... not dangerous but load has suboptimal powder burnt with possible characteristics such as extensive muzzle flash or inaccurate loads.

[...] ²... fill rate low - you might want to consider using a filler to ensure proper ignition.

[...] ᴾ... possible press load - work up slowly to this load while watching for signs of excessive pressure.

👍 ... recommended powder/load for this caliber and bullet combination based on its ballistic performance.